Ellipsograph



1952 w. J. FLEETWOOD 2,607,991

ELLIPSOGRAPH Filed June 15,. 1949 2 SHEETSSHEET l .Z Zz'e'r. 6.

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Aug.26, 1952 Flled June 13 1949 Patented Aug. 26, 1952 invention relates a draftinginstrument for drawing ellipses, and has asan object --the provision of an instrument of the type generally known as-an ellipso'graph wherewith-ellipses may beaccurately- -drawn to' specified dimensions.

A-further object of the invention is to provide an 'el-lipsograph which is "horizontally compact inrelation to-themaximmn-size of ellipse which it is designed-to draw; "so that the-instrument "may be conveniently handledona"drawing-board or paperofreasonablesize;

Another object of the invention 'is' "to provide an ellipsograph which is simple to operate, requirin'g adjustment of only-two elements, "gov-- erning respectively the major diameter and the minor-diameter of the ellipse; "and not involvin bread knowldege-of mathematics on the part of the draftsman. I

Still anotherbbjectof the invention is to PIL videanellipsograph capableof drawing a straight line or an ellipse having thatline as a -major axis and" an axialratio -apprcach-ing closely to unity. My-invention possesses othenobjec-tsand ad- H l :Fleetwood, Los Angelegflalif.

' p Applicationilune 1s,1949;s iisrnwaascs ZCI-aims. (01.533530) V 1L2 f-, -1 my invention hyrnounting a scribe-r so *that it as free to travel in-alidirections parallel to a paper or other surface to b-e inscribed, and 11 1 contact with the papergand connecting the 'scriber, by means of a joint pennitting universal -movemen-t, to one endoi a-bent-arm-or crank,--th -e ether-end of which isjournalletl-rotatably.- Rotationefthe journal-led end *o-f the crank causes the universal joint at theother end-to describe-a circle menace,

and the scriber'mu-st necessaril-y fellow *the'gyratio-n of the universal j oi-nt,-'neverthelessremain ingperpendicular to thepaper. 'By-inch-ningthe journal orthe crank'ata selected angleto-the paper; the-scrib'er is'caused to inscribe upon t e paper '"a proiection of the circle "at an angle projection, or in other words anell'ips'e; By-- tering "thecrank angle; the diameter o f the cir' in space may be varied, the major diameter the resultant--ellipse -being"twice thethrow-of crank; The=three-dimensionalmovement of the connection between the crank and the scriber' permitsthe entireme'chanism to'be concentrated vantages which" will be specfficallyppinted'out as p the following description of a preferred embodiment'fofthe-invention proceeds; "or'will be apparent fromconsideration "of the accompanying drawings, illustrative of that embodiment, in h h: fi ge ss t ve i i an e i oe a h embodying'the principles of my invention, the particular adjustment shown therein being that br inea'si e me;

Fig 2'iis'a schematicyiew showing the minor axial fcentrol'adjusted 1 for drawing an ellipse and illustr'atingthe manner of projecting a circle at adesired axial 'ratio nn'anglje of projection upon a draftingsurface;

Fig-L 3 -is aside elevationai view on an enlarged scale, the-minor axialcontrolb'eing shown in full line in the position of-Fig. 1 anddn' brcken' line in the position of Fig: 2;

-'-'-Fig. 4' is a top plan-view;

"F ier-E isa further-enlargeddetail' view'o-fmeans employed for locking a carrier cable to a novehl'e scriber; 1 V

Fig; 6. is a horizontal sectional viewonan en larged- 'scale 'taken en the plane-'ofsecticn'ilndicated by theline- 6-6 "of 3, and 109king downward; and-- :Fig; 7 is a fragmentary vertical sectional View, on=approximately-the-scale"ofFig. 6, andtaken'on the plane of section indicated by the line T-r-ZTiOf Ins eneral terms; I accomplish the purposes of in-a spacen-ot inconvenient to-thedraftsm-an'and afiording '-f-ull----visibility--of the figur drawn:

Specifically describing the details of the--preferred embodiment of my invention as herewith illustrated, -I have shown a frame Hi com: prising a =base-l-land-a hinge post lierected thereon and 'pivotally "supporting a two-armed bracket I53; The upper and-lower arms, Mfandl5, respectively are parallehone above -t--,he-"othe'r,

and swing in planes parallelto a surface 'tdbe inscribed, such'as a sheet-of paper "I i-on which the base H may 'rest Each of the-arms-com prisesside rails -|-'l'-j'oined at their distal "ends journal pins Iii-and at theirproximal ends=-by journal pins It and 218-; which latter aredisposed approximate'ly'one above the o'then --A-sheave"2fl 7 upon the journal "pin 18" of the upper'arm and-shea es and u u n-t journal p s 1 d ?.0' .1- he up e mn ke rhe 'i u ns 8, l9; a 209 he o 111 1 rotat bl support sheav 1 25 nd" 25' s cti e ch f he a ms thus d nes slot 21, bounded atthe sides'by therails" H and at the ends by the sheaves respective thereto.

A ri 91s m unted mine 0i s 0 lie-closely guided therein-bytherails l -1' in movee ment between the distaland proximal endsfof the;

arms; The scribe'r'3fl-may be any type 'oiin strument suitable for 'drawingf or engraving, such as for example a's'haft'havig a nib' o'r drawin point 3 1 at'its-lower'en'd A cable 3- supports the scriber Q I D DE 'F ularly to the" paper 1 6', piercing the 'scriber' ferred method of securing the ends of the cable 33 is shown in Fig. 5. A threaded recess 38 in the upper end of the scriber extends downwardly therein to the level of the hole 34 and receives a plug 39 which has a central bore 43. The ends of the cable 33 are threaded through opposite ends ofth'e hole 34 into the recess 38 and are drawn upwardly through the bore 40 of the plug 39. When the plug 39 is screwed down to the end of the recess 38 it firmly clamps the ends of the cable, which may be easily adjusted for tension by slightly loosening the plug.

The cable 33 extends from its fasteningpoint at the plug 39 outwardly over the'end sheave 2|, thence inwardly and freely through the hole 35 to the sheave 23, and downwardly and around the sheave 25 and thence outwardly to the hole 35 in the lower end of the scriber. As the cable passes through the hole 35 it is secured therein by a set screw 42. A hole 43 in the arm I5 permits entrance of a tool for adjusting the set-screw when the scriber, is moved to alignment with that hole. Fromits fastening point in the hole a s 35, the cable extends outwardly around the sheave 24, thence inwardly and freely through the hole 31 and thence'around the sheaves 26 and 22 to its fastened termination in the plug 39. By reference to Fig. 3 it will be seen that this con struction provides a cable strand at the level'of the arm I4 which is movable in the same direc tion as a cable strand at the level of the arm l5, these like-moving strands being parallel and secured to the scriber 30. A pressure vector upon the scriber 30 parallel to the arms [4 and I5 will causethe scriber to move along the slots 21," but the two ends of the scriber will always be constrained by the cable 33 to move atthe same rate of speed, so that the scriber is maintained perpendicular to the arms l4 and I5 and to the paper l6, and is restrained by the cable from movement perpendicular to the surface of the paper.

A sleeve 44 is mounted on a hub 45 pivotable on a trunnion pin 45cm the frame 10 so as to be pivotable in a plane parallel to the axis of the scriber 30. A graduated scale 41 is provided to show the inclination of the sleeve with respect tothe base II and paper I6. The'trunnion pin :46 is threaded to receive a nut 48 by which it may be locked at a selected inclination as indexed by a mark 49. A shaft 50 extendsIrotatably through the sleeve 44 having a handle on its one end and being threaded into the bight or head 52 of a clexis 53 at its other end. A second shaft or connecting rod 54 is pivoted on the pin 55 of the clevis 53. As the bearing head 56 of the connecting rod 54 is in alignment with the end of the shaft 50, turning the shaft 50 to advance it through the clevis bight 52 will tighten it upon the bearing head 55 and so lock the connecting rod 54 at any selected angle to the shaft 50. V

Theconnecting rod 54 may conveniently be made in three pieces as shown in Fig. 6, comprising a central shaft 58 into one end of which the bearing head 56 is threaded and into the other end" of which a swivel head 59 is threaded. A clevis so is mounted on the swivel head 59,. the swivel head 59 extending through the clevis head and being rotatable in the bight thereof. The

shaft 51] and rod 64 obviously ferm a crank of 4 selectable angularity, of which the elbow, the clevis pin 55, is movable through an are perpendicular to a surface on which the ellipsograph stands.

A collar 65 is mounted on the scriber 3B and is slidable thereon and rotatable thereabout. Trunnion pins 3'5 on the sides of the collar 65 are engaged by the arms of the clevis 60. As the clevis 60 can rotate with the collar 65 around the scriber 30 in one plane and-"can pivot on the trunnion pins 65 in a perpendicular plane and may swivel on the swivel head 59, the collar 65, clevis W, and swivel head 59 form a universal joint capable or relative rotary motion of its end -lipsograph is placed on the paper so that marks 56 on the base ll, aligned with the shaft 50, are aligned with the center of the proposed ellipse. The minor axis of the ellipse will lie in prolongationof the line defined by themarks 68. If the diameters are known, the connecting rod 54 is held in aligned prolongation of-the shaft 50, both of which are held parallel to the paper I5, and the connecting rod is then swung in a plane parallel t the paper until the collar 65 and the scriber controlled thereby are moved laterally one-half the length of themajor diameter of the ellipse. ,"I he scriber will then be stationed at one end of the major diameter. The shaft 50 may then be rotated to advance to a locking position against the bearing head 56 of the connecting rod, the connecting rod being held steady to provide a resistance- With the nut loosened, the minor diameter is obtained by tilting the sleeve 44 and shaft 50.1 The nut iais -then: tights; ened. Rotation of the shaft 50 by turning the handle 5! in the direction tending totightenthe lock upon the connecting rod 54 causes the collar- 65 to describe'a circle in spacefduring which gyration the collar guides the scriber 33 so that the drawing point 3i inscribes a projection of the circleupon the paper l3. "This projection is the desired ellipse. As appears'froin Fig. 2, this circle in space may'lie in a planeinclined to the paper at less than degrees and yet be disposed entirely beyond the zone through which any part The inclination of the circle described bitlie' collar 65 will be complementary to theinclination of the shaft5il, with reference to'the'paper l6,

7 It should be noted that rotation of the shaft 50.. when the shaft .53 and conniecting rod 54 are;

aligned'and not tilted produces no movement of the scriber 30; and that rotation when the shaft and rod are. angulated but not tilted producesa of the shaft50 increases, the axial rafiohf the ellipse drawn approaches unity, the ellipse approaching' circular form, As herein shown, my

invention is not capable of drawing a circle; requ1r1ng a vertical position of the shaft 50, but an angle of projectionof from twenty to ninety (the straight line). degrees may be achieved for small.

ellipses.

" Obviously my invention is subject to mosses...

3 1 33}? an and ar an emen pr its elem n axis of Fig. 2, As thetilt.

therefore, I do not wish to be limited to the exemplification herein described and illustrated, the spirit and scope of the invention being expressed in the appended claims.

I claim:

1. A device for drawing ellipses, comprising: a frame; guide means pivoted on said frame for movement parallel to a surface to be inscribed; a scriber carried by said guide means perpendicularly to said surface and having freedom of lateral movement longitudinally of said guide means; a collar slidable on said scriber; laterally extending pins on said collar; a first clevis engaging said pins; a first shaft swivelly joined at its one end to said first clevis; a second shaft; a second clevis threadedly secured to one end of said second shaft and pivotally connected to the other end of said first shaft, threaded advancement of said second shaft in said second clevis into contact with said first shaft serving to lock said shafts in angular relationship; a sleeve for said second shaft, pivotally mounted on said frame; means for securing said sleeve to said frame so as to hold said second shaft at selected inclinations to said surface; and means for rotating said second shaft, whereby said collar is caused to describe a circle determined as to diameter by the angular relationship of said shafts and as to inclination to said surface by the inclination of said second shaft to said surface, and said scriber is caused to move laterally to inscribe a projection of said circle on said surface.

2. A device for drawing ellipses, comprising: a frame; a member pivoted on said, frame having a pair of radially extending arms, each of said arms having a longitudinal slot; a scriber held 6 slidably by said arms within said slots; a sheave at the distal end of each of said arms; a pair of sheaves at the proximal end of each of said arms; a cable trained around said distal sheaves and then around said pairs of sheaves so as to provide cable strands movable in like direction and parallel to each other between said distal sheaves and the adjacent pair of sheaves, two of said like-moving strands being secured to said scriber so as to hold said scriber at a fixed angle to said arms while permitting said scriber to move laterally along said slots; a collar slidable on said scriber; a jointed arm connected to said collar to have universal movement with respect thereto; means for securing the distal portion of said jointed arm at selected angles to the proximal portion of said jointedarm; means for securing the proximal portion of said jointed arm at selected inclinations to said frame; and means for rotating said jointed arm.

WILLIAM J. FLEETWOOD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 677,590 Oldfield July 2, 1901 828,372 Becker Aug. 14, 1906 2,468,017 Aichroth Apr. 26, 1949 FOREIGN PATENTS Number Country Date 141,400 Great Britain Apr. 12, 1920 436,830 Great Britain Oct. 18, 1935 143,226 Austria Oct. 25, 1935 

